An apparatus of this type is known from the prior art and is frequently called an oxygenator and is used to lower the CO2 partial pressure and to raise the O2 partial pressure by material exchange, particularly a gas exchange via the permeable walls of the fiber tubes. For that purpose, a gas or gas mixture is passed through the fiber tubes such that the CO2 partial pressure is lower than in the blood and the O2 partial pressure is higher, resulting in a compensation of the partial pressures through a material exchange due to diffusion of the gas molecules, and thus in oxygen enrichment and CO2 depletion in the blood.
Such an oxygenator or apparatus of the this type can be used as an artificial lung, and according to the previous prior art such an apparatus is essentially used outside the body.
A problem with the use of such an apparatus occurs particularly when it is provided to completely take over the function of the lung, for example in patients waiting for a lung transplant. This is a problem insofar as, due to the flexibility of the pulmonary vessels and particularly the pulmonary artery, a so-called windkessel effect, i.e. an elastic flexibility of the vessels in case of blood fluctuations due to the heartbeat that is provided by these organs or organ regions, is omitted, and since the heart must pump against increased resistance, when a rigid apparatus for material exchange is used, it is medically questionable.
Against this backdrop an apparatus has already been developed, in which the outer housing has a flexible wall that is flexible with regard to the pulsating blood pressure insofar as the housing volume reacts to the blood pressure and increases with elevated blood pressure, and the outer dimensions of the entire apparatus increase in size. The apparatus of the above-described type are large by comparison and not very suitable for a preferred use inside the body.